title: Controlled formation of silica structures using siloxane/block copolymer complexes prepared in various solvent mixtures.
abstract: Block copolymers exhibit regularly patterned structures induced by microphase separation. Here we present a method for preparing various particulate silica (SiO2) nanostructures by controlling the microphase separation of block copolymers. In this method, siloxane, a SiO2 precursor, is adsorbed onto poly(4-vinylpyridine) blocks of polystyrene-block-poly(4-vinylpyridine) in solvent mixtures. After siloxane/polymer complexes are coprecipitated via further siloxane polycondensation, the resulting precipitates are heated to remove the polymer. The results of scanning electron microscopy revealed that SiO2 formed various structures including cylindrical, spherical, and lamellar. Different SiO2 nanostructures formed via the microphase separation of siloxane/polymer complexes are prepared simply by varying solvent mixtures without changing the polymer chain. The structural change is interpreted in terms of polymer-solvent interactions and volume fractions in siloxane/polymer complexes.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Kataoka
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Akiko
authors.initials: A
authors.lastname: Kawai
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Yamada
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kamimura
authors.forename: Akira
authors.initials: A
authors.lastname: Endo